Is there a way of borrowing say a tail or wings off one model and putting on another?
Yes, but it depends...
Some are much easier to reuse than others.
A tail can be an integral part of the model (like the cat's tail in Millenium Cat figure), an add on prop or figure like clothing or hair. The latter two types are easiest to transfer.
What are you wanting to reuse? It will be easier with knowing what type of 'part' it is...